1. Field of the Invention
The present invention relates to mobile paging telephone call back systems and methods. More particularly, the present invention relates to systems and methods for adding appropriate prefixes to received telephone numbers to permit automatic dialing of the telephone numbers by a mobile telephone device.
2. Description of Related Art
Today's mobile cellular telephones offer tremendous communication advantages for mobile consumers. Because cellular telephones often exhibit poor reception qualities and consume power quickly, however, cellular companies have begun to incorporate paging receivers into cellular telephones. With the paging receiver, the cellular telephone can be turned off, conserving battery life, while the paging receiver remains on monitoring for calls. Battery life is conserved because the power to energize a paging receiver is comparatively low. An example of a mobile paging telephone call back device is disclosed in commonly assigned U.S. Pat. No. Re. 33,417 ("the '417 patent"), entitled "Mobile Paging Call Back System and Related Method," by Bhagat et al., the contents of which are hereby incorporated by reference.
FIG. 1 is a block diagram of a mobile paging telephone call back device 10, as described in the '417 patent. The mobile paging telephone call back device 10 includes a control unit 12 connected to a radio pager 14, a memory 16, a radio telephone interface 18, control switches 20, and an indicator 22. The radio telephone interface 18 is also connected to an intelligent automatic dialer 24, which is in turn connected to a mobile radio telephone 26.
The device 10 operates as follows: a caller wishing to reach a subscriber (a user of the mobile paging telephone device 10) calls a paging station (not shown), leaves a call back telephone number, and, typically, hangs up. The paging station then transmits the call back telephone number over the air. The radio pager 14 receives the call back telephone number and passes it to control unit 12. The control unit 12 processes the number, stores it in memory 16, and displays it on indicator 22. A subscriber wishing to return the call presses a control switch 20, activating the automatic dialer 24 to dial the displayed call back telephone number.
Mobile paging telephone devices, like call back device 10, greatly conserve the battery life of the cellular telephone, which, as described, can be turned-off, then turned-on when a page comes in. Today's mobile paging telephone devices suffer, however, from one nagging disadvantage; they often cannot complete the call back because the call back telephone number lacks the appropriate prefix, such as an area code or a "1", necessary to complete the return call. For example, a calling party may be unaware of the location of the subscriber and fail to include the prefix "1" and area code when he or she enters the call back telephone number. This information may be necessary to complete a long distance dial back call. Conversely, the calling party may unnecessarily include a "1" or an area code in the call back telephone number, thinking the subscriber is away, when the subscriber is actually local. This problem is compounded in areas where dialing plans require a prefix, such as an area code, to complete even local calls.
In each of the above situations, conventional mobile paging telephone devices cannot automatically complete a call using the call back number as received. Instead, the subscriber must manually dial all or part of the call back number including the appropriate prefix. If the subscriber does not know the appropriate prefix, he simply cannot return the call.